This is the use of silicon controlled phase shifting principle to realize motor voltage regulator starting, mainly used for motor start-up control, starting effect is good but the cost is higher. Because of the use of SCR components, SCR work when the harmonic disturbance is larger, the power grid has a certain impact. In addition, the fluctuation of power grids can affect the guide of SCR elements, especially when there are multiple SCR devices in the same power grid. Therefore, the failure rate of SCR components is higher, because the power electronic technology is involved, so the requirements for maintenance technicians are also higher.